/Engine/Source/Runtime/AudioMixer/Public/AudioMixerBlueprintLibrary.h
Queries if the given audio bus is active (and audio can be mixed to it).
static bool IsAudioBusActive ( const [UObject](API\Runtime\CoreUObject\UObject\UObject) * WorldContextObject, [UAudioBus](API\Runtime\Engine\Sound\UAudioBus) * AudioBus )